EP3564629B1 - Sensor device and method for producing same - Google Patents

Description

TECHNICAL AREA

The invention relates to the field of solar-powered sensor devices, in particular for the field of home automation in interior spaces. The invention also relates to a method of manufacturing such sensor devices.

TECHNICAL BACKGROUND

In the course of the development of home automation, measuring devices are increasingly being used that measure environmental parameters such as temperature, humidity, pressure, brightness, gas concentration, dust, vibration, etc. Typically, such measuring devices are used indoors and equipped with an autonomous energy supply, i.e. without a mains supply. For example, the measuring devices can be operated with a battery. Alternatively, the measuring devices can be operated by generating ambient energy, e.g. by using solar cells. For reasons of cost and robustness, silicon-based solar cells are increasingly being used.

In particular, it has been found that for light conditions with low irradiance, in particular under artificial light, based on amorphous silicon (a-Si) Solar cells are the preferred choice. A disadvantage of a-Si solar cells is that, due to their typically dark brown optical appearance, they form a clear contrast to the measuring devices and their mounting environment and are therefore often judged to be unaesthetic. Since measuring devices for home automation are typically installed and mounted in visible places, for example on ceilings, walls or the like, adaptability of the optical appearance of the measuring device to the installation environment is of great interest.

For realizing the adaptability of the optical appearance of solar cells, colored solar cells based on Si are known from the prior art. The colored solar cells known from the prior art are, however, quite cost-intensive, since special process steps have to be used in their manufacture. For this reason, solar cells of this type are not suitable for mass products, in particular for measuring devices for use in home automation. Furthermore, known solutions for adapting the optical appearance of solar cells are mainly designed for solar applications in the outdoor area, so that these are poorly suited for the indoor area, where comparatively weak light conditions prevail.

Since measuring devices used in home automation are typically attached to light-colored, in particular white, walls, there is a demand for photovoltaic-operated measuring devices with a light, in particular white, optical appearance. Physical reasons make it difficult to reconcile such an appearance with a high photovoltaic output or conversion efficiency. To get a light or white appearance achieve, a large part of the incident light must be reflected and / or scattered by the surface over the entire visible wavelength range. On the other hand, the spectral sensitivity of a-Si solar cells is highest in the visible wavelength range, so that usually a light appearance can only be achieved with high efficiency losses.

The documents refer to the state of the art by way of example JP 2016 157356 A and DE 10 2006 032250 A1 referenced. document JP 2016 157356 A describes a wireless sensor terminal with a solar cell module as a power supply. document DE 10 2006 032250 A1 relates to an energy supply unit for a field device for measuring a pressure or a fill level, a field device with such an energy supply unit, the use of an energy supply unit for a field device and a method for supplying energy to such a field device.

The object of the present invention is to at least partially or completely eliminate the disadvantages of the solutions known from the prior art for adapting the optical appearance of a sensor device operated by means of photovoltaics to its installation environment.

SUMMARY OF THE INVENTION

To achieve the above-mentioned object, a sensor device and a method for producing a sensor device according to the independent claims are provided. Further aspects, advantages and features of the present invention can be found in the dependent claims, the description and the accompanying figures.

According to one aspect of the invention, a sensor device is provided. The sensor device comprises at least one sensor and a housing for the at least one sensor. Furthermore, the sensor device comprises at least one solar cell for supplying energy to the at least one sensor, the at least one solar cell being attached to an outer wall of the housing. The term “solar cell” used herein can also be understood as “solar module”. The attachment of the solar cell to the outer wall of the housing can be implemented by fastening on the outside of the housing or on the inside of the housing (for example in the case of a transparent housing). Alternatively, the solar cell can be integrated into the outer wall of the housing. Furthermore, the sensor device comprises a cover which covers a photovoltaically active side of the at least one solar cell. The cover comprises a translucent material, in particular the cover consists at least for the most part of a translucent material.

In this way, a sensor device that can be operated by means of photovoltaics is advantageously provided, which can be optically adapted to its installation environment without unduly impairing the energy conversion efficiency of the solar cell. In particular, by using a translucent material for the cover, a cost-effective, functional and aesthetic sensor device that can be operated by means of photovoltaics can be provided.

According to a further aspect of the invention, a method for producing a sensor device is provided. The method comprises the following method steps: producing a housing for at least one sensor, the housing having a receptacle for at least one solar cell; Producing a cover from translucent material, the cover being adapted to the housing; Providing at least one sensor in the housing; Placing a solar cell in the receptacle; Establishing an electrical connection between the at least one solar cell and the at least one sensor; and mounting the cover on the housing in such a way that the cover covers a photovoltaically active side of the at least one solar cell, in particular that the cover directly Contact is in direct contact with the photovoltaically active side of the at least one solar cell.

A simple and cost-effective production method for a photovoltaic-operated sensor device is thus advantageously provided, which can be optically adapted to its mounting environment without unduly impairing the power efficiency of the solar cell.

BRIEF DESCRIPTION OF THE FIGURES

Figur 1

eine schematische Schnittansicht einer Sensorvorrichtung gemäß hierin beschriebenen Ausführungsformen;

Figur 2A

eine schematische Draufsicht einer Sensorvorrichtung gemäß hierin beschriebenen Ausführungsformen ohne Abdeckung;

Figur 2B

eine schematische Draufsicht einer Sensorvorrichtung gemäß hierin beschriebenen Ausführungsformen mit Abdeckung;

Figur 3

eine schematische Schnittansicht eines Ausschnitts einer mit einer Solarzelle in Kontakt stehenden Abdeckung gemäß hierin beschriebenen Ausführungsformen; und

Figur 4

eine Flussdiagramm zur Veranschaulichung eines Verfahrens zum Herstellen einer Sensorvorrichtung gemäß hierin beschriebenen Ausführungsformen.

Furthermore, the invention is to be explained on the basis of exemplary embodiments shown in the figures, from which further advantages and modifications result. Here shows:

Figure 1

a schematic sectional view of a sensor device according to embodiments described herein;

Figure 2A

a schematic top view of a sensor device according to embodiments described herein without a cover;

Figure 2B

a schematic top view of a sensor device according to embodiments described herein with a cover;

Figure 3

a schematic sectional view of a detail of a cover in contact with a solar cell according to embodiments described herein; and

Figure 4

a flowchart for illustrating a method for producing a sensor device according to embodiments described herein.

DETAILED DESCRIPTION OF THE FIGURES

Figure 1 shows a schematic sectional view of a sensor device 100 according to embodiments described herein. The sensor device 100 comprises at least one sensor 110 and a housing 120 for the at least one sensor 110. For example, the at least one sensor 110 can comprise one or more sensors selected from the group consisting of temperature sensor, humidity sensor, pressure sensor, light sensor, acoustic sensor, magnetic field sensor , Gas concentration sensor, dust sensor, and vibration sensor or other suitable micro-electromechanical (MEMS) sensors are selected. For example, the sensor device described herein can be a home automation sensor device, in particular for interiors.

Furthermore, the sensor device 100 comprises at least one solar cell 130 for supplying energy to the at least one sensor 110. The at least one solar cell is typically a silicon-based solar cell. For example, the solar cell can be a solar cell based on amorphous silicon (a-Si).

As exemplified in Figure 1 As shown, the solar cell 130 is attached to an outer wall 121 of the housing 120. In particular, the solar cell 130 is attached to an outer wall of the housing, which is irradiated with direct or at least diffuse light in the assembly environment. The outer wall 121 of the housing 120, to which the solar cell 130 is attached, is typically arranged opposite a mounting side 123 of the housing. The mounting side 123 is to be understood as that side or that wall of the housing which is used to mount the sensor device on a mounting surface, for example a wall. In other words, in the assembled state the mounting side 123 of the housing is more typically in contact with the mounting surface at least partially indirectly (eg with spacers) or directly (ie directly without spacers). Alternatively or additionally, one or more solar cells can be attached to one or more of the side walls 124 of the housing (not explicitly shown in the figures).

In addition, the sensor device 100 comprises a cover 140, as shown schematically in FIG Figure 1 is shown. The cover 140 is designed in such a way that it covers a photovoltaically active side 131 of the solar cell 130. The photovoltaically active side of the solar cell is typically a side of the solar cell facing away from the housing. According to the invention, the cover 140 comprises a translucent material 141. In particular, at least that part of the cover 140 which covers the solar cell 130 consists of a translucent material 141. Typically, at least 80% of the cover consists of translucent material. According to one embodiment, the entire cover 140 consists of a translucent material.

Accordingly, the embodiments described herein provide a solution, which is improved over the prior art, for adapting the optical appearance of a sensor device operated by means of photovoltaics to its mounting environment. In particular, a sensor device that can be operated by means of photovoltaics is provided, which can be optically adapted to its installation environment without unduly impairing the power efficiency of the solar cell. In particular, by using a translucent material for the cover, an inexpensive and easily manufactured sensor device with a homogeneous appearance can be achieved to be provided.

By using a translucent material, the cover is advantageously designed in such a way that incident light is scattered by the cover in the visible spectral range and thus optically covers the solar cell. At the same time, the energy conversion of the solar cell is advantageously only slightly impaired. This means that the cover has a high optical transmission in the spectral range relevant for the solar cell.

According to one embodiment, which can be combined with other embodiments described herein, the cover 140 is in direct contact with the photovoltaically active side 131 of the solar cell 130. This advantageously makes it possible to achieve a high integral transmission, since optical interface effects can be avoided.

According to one embodiment, which can be combined with other embodiments described herein, a defined distance is provided between the cover 140 and the photovoltaically active side 131 of the solar cell 130. In this way, a high integral transmission can advantageously be achieved, since the diffuse transmission of a larger proportion of the cover 140 can be used. An example of this would be that light can also reach the solar cell 130 through the side walls 124, so that if the sensor device 100 is at least partially irradiated from the side, a higher energy conversion would be achieved by the solar cell 130.

Figure 3 FIG. 10 shows a schematic sectional view of a detail of a cover 140 according to the embodiments described herein that is in direct contact with a solar cell 130 stands. The irradiated light is shown by way of example by the arrows 150. Reflected light components are shown by the arrows 151. The light components arriving at the solar cell are on the one hand the directly transmitted light components (shown by the arrows 153) and the diffusely (scattered) transmitted light components (shown by the arrows 152).

According to one embodiment, which can be combined with other embodiments described herein, the translucent material has an integral transmittance Tint of, for example, T _int 70%, in particular T _int 80%, in particular T _int 85%. For example, the integral transmittance Tint of the translucent material Tint can be 90%. The direct transmittance T _{d of} the translucent material is typically relatively low. For example, the direct transmittance T _{d of} the translucent material can be T _d 10%, in particular T _d 8%, in particular T _d 5%. The direct transmittance T _{d is} typically 3%. It should be pointed out that the values for the integral transmittance Tint and the values for the direct transmittance T _{d can be set} according to the desired appearance, for example in order to achieve a suitable compromise between appearance, transmission and costs.

The values given here for the integral transmittance T _int and the values for the direct transmittance T _d apply to the wavelength range 350 nm λ 1200 nm, in particular for the wavelength range 400 nm λ 1100 nm.

Accordingly, the translucent material is advantageously configured in such a way that the scattered light component of the integral transmittance is relatively high, so that a homogeneous Appearance of the cover and thus the sensor device can be realized. In particular, with the embodiments described herein, a homogeneously bright, in particular white, appearance of the cover and thus of the sensor device can advantageously be realized.

According to one embodiment, which can be combined with other embodiments described herein, the optical transmission of the translucent material and the quantum efficiency of the solar cell are matched to one another. This means in particular that the optical transmission of the translucent material is particularly high at the wavelengths at which the solar cell has a high energy conversion efficiency.

According to one embodiment, which can be combined with other embodiments described herein, the translucent material consists of a thermoplastic material. This has the advantage that the cover can be produced from translucent material by means of an injection molding process or by means of an extrusion process. In particular, the translucent material can comprise a polymethyl methacrylate (PMMA). Alternatively or additionally, the translucent material can comprise a polycarbonate (PC).

According to one embodiment, which can be combined with other embodiments described herein, the housing 120 for the at least one sensor 110 can also be produced from a thermoplastic material, in particular from the same thermoplastic material as the cover 140. In this way, inexpensive, functionally and optically optimized sensor devices can advantageously be provided. In this case, the housing can function as a cover in one Integrate component. This functional integration allows the assembly effort and thus costs to be reduced.

According to the invention, particles 145 with light-scattering properties are embedded in the translucent material, as is exemplified in FIG Figure 1 is shown. For example, the particles 145 can be colored to adapt the optical appearance of the cover. In other words, by adding particles with light-scattering properties, the light-scattering property of the cover is adjusted.

According to the invention, the translucent material is adapted in such a way that it converts incident photons of the incident light into wavelengths at which the quantum efficiency of the solar cell is higher than the wavelengths of the original incident light. According to the invention, this is implemented through the use of fluorescent materials. In particular, the use of PMMA can provide a translucent material with fluorescent properties, so that the integral transmittance can be improved, i.e. increased.

According to an embodiment that can be combined with other embodiments described herein, the cover 140 can be plate-shaped, as is exemplified in FIG Figure 1 shown. Typically, the cover 140 can be connected to the housing 120 via suitable fastening means. The fastening means can be provided, for example, by a snap or slide mechanism between cover 140 and housing 120. Alternatively or in addition, screws or other suitable fastening means can also be used.

How exemplary Figure 1 is apparent, the cover is typically adapted to the shape of the housing. For example, the cover 140 can be configured such that the cover at least partially engages around the side walls 124 of the housing 120. Figure 1 shows an exemplary embodiment in which the cover 140 completely encompasses the side walls 124 of the housing 120.

According to an embodiment that can be combined with other embodiments described herein, the housing 120 has a light-permeable section 122, as is exemplified in FIG Figure 1 is shown. For example, the translucent portion 122 can be an opening in the housing. The provision of a transparent section 122 in the housing is particularly advantageous for a configuration in which at least one sensor is designed as a light sensor. In this case, the light sensor is typically arranged below the light-permeable section 122, as is exemplified in FIG Figure 1 is shown.

According to one embodiment, which can be combined with other embodiments described herein, the housing 120 has a receptacle 125 for the solar cell 130. For example, the receptacle can be a recess in the outer wall 121 of the housing to which the solar cell is attached.

According to one embodiment, which can be combined with other embodiments described herein, the cover 140 completely covers the outer wall 121 of the housing to which the solar cell is attached, as is exemplified in FIGS Figures 2A and 2B emerges. Figure 2A shows a schematic top view of a sensor device according to embodiments described herein without a cover and FIG Figure 2B shows a schematic top view of a sensor device according to embodiments described herein with cover 140.

According to one embodiment, which can be combined with other embodiments described herein, the outer wall 121 of the housing 120, to which the solar cell is attached, has a first roughness value R _a1 , which is adapted to a second roughness value R _{a2 of} the solar cell 130, in particular so that 0.75 · R _a2 ≤ R _a1 ≤ 1.25 · R _a2 . This can be advantageous in order to achieve a homogeneous appearance.

Figure 4 FIG. 10 shows a flow diagram to illustrate a method 200 for producing a sensor device according to embodiments described herein. The method 200 comprises the following method steps: producing (represented by block 210) a housing 120 for at least one sensor 110, the housing having a receptacle 125 for a solar cell 130; Manufacture (represented by block 220) a cover 140 made of translucent material, comprising a fluorescent material, whereby impinging photons of the incident light are converted into wavelengths at which the quantum efficiency of the solar cell is higher than at the wavelengths of the originally incident light, the cover 140 is adapted to the housing 120; Providing (represented by block 230) at least one sensor in the housing; Placing (represented by block 240) a solar cell 130 in the receptacle 125; Establishing (represented by block 250) an electrical connection between the solar cell 130 and the at least one sensor 110; and mounting (represented by block 260) the cover 140 on the housing such that the cover 140 covers in direct contact with the photovoltaically active side 131 of the at least one solar cell 130, in particular that the cover 140 is in direct contact with the photovoltaically active side of the at least one solar cell is available. Alternatively, the cover 140 can also be mounted on the housing in such a way that between the cover 140 and the photovoltaically active side 131 of the at least one solar cell 130 is provided a defined distance.

According to the invention, the production 220 of the cover 140 includes embedding particles 145 with light-scattering properties.

According to one embodiment of the method for producing the sensor device, which can be combined with other embodiments described herein, the production 210 of the housing 120 and / or the production 220 of the cover 140 comprises an injection molding process and / or an extrusion process.

As can be seen from the embodiments described herein, a sensor device operated by means of photovoltaics and a corresponding manufacturing method are advantageously provided which, compared to the prior art, enable an improved and more cost-effective solution for setting and adapting the optical appearance without unduly impairing the energy conversion efficiency of the solar cell.

REFERENCE LIST

100

Sensor device

110

sensor

120

casing

121

Outer wall of the housing

122

translucent portion of the housing

123

Mounting side of the housing

124

Side walls of the housing

125

Holder for the solar cell

130

Solar cell

131

photovoltaically active side of the solar cell

140

cover

141

translucent material

145

Particles with light-scattering properties

200

Method for manufacturing a sensor device

210

Method step: producing a housing for at least one sensor

220

Process step: production of a cover from translucent material

230

Process step: providing a sensor

240

Process step: placing a solar cell

250

Process step: Establishing an electrical connection

260

Method step: mounting the cover on the housing

Claims (16)

1. Sensor apparatus (100) comprising:

   - at least one sensor (110);

   - a housing (120) for the at least one sensor (110);

   - at least one solar cell (130) for supplying energy to the at least one sensor (110), wherein the at least one solar cell (130) is mounted on an external wall (121) of the housing (120); and

   - a cover (140), which covers a photovoltaically active side (131) of the at least one solar cell (130), wherein the cover (140) comprises a translucent material (141), wherein particles (145) having light-scattering properties are embedded in the translucent material, and wherein the translucent material comprises a fluorescent material through which incident photons of the incoming light are converted into wavelengths in which the quantum efficiency of the solar cell is greater than in the case of the wavelengths of the original incoming light.
2. Sensor apparatus (100) according to Claim 1, wherein the cover (140) is in direct contact with the photovoltaically active side (131) of the at least one solar cell (130).
3. Sensor apparatus (100) according to Claim 1, wherein a defined distance is provided between the cover (140) and the photovoltaically active side (131) of the at least one solar cell (130).
4. Sensor apparatus (100) according to one of Claims 1 to 3, wherein the cover (140) completely covers the external wall (121) of the housing on which the at least one solar cell is mounted.
5. Sensor apparatus (100) according to one of Claims 1 to 4, wherein the external wall (121) of the housing (120), on which the solar cell is mounted, has a first roughness value Rai, which is adapted to a second roughness value R_a2 of the at least one solar cell (130), so that 0.75·Ra₂ ≤ Ra₁ ≤ 1.25·Ra₂.
6. Sensor apparatus (100) according to one of Claims 1 to 5, wherein the optical transmission of the translucent material of the cover (140) and the quantum efficiency of the at least one solar cell (130) are matched to one another.
7. Sensor apparatus (100) according to one of Claims 1 to 6, wherein the translucent material consists of a thermoplastic material, in particular comprising polymethyl methacrylate (PMMA) and/or polycarbonate (PC) .
8. Sensor apparatus (100) according to one of Claims 1 to 7, wherein the cover (140) is produced by means of an injection-moulding method or by means of an extrusion method.
9. Sensor apparatus (100) according to one of Claims 1 to 8, wherein the housing (120) has a holder (125) for the at least one solar cell (130).
10. Sensor apparatus (100) according to one of Claims 1 to 9, wherein the at least one solar cell (130) is a silicon-based solar cell, in particular a solar cell based on amorphous silicon.
11. Sensor apparatus (100) according to one of Claims 1 to 10, wherein the at least one sensor (110) comprises one or more sensors selected from the group consisting of: temperature sensor, humidity sensor, pressure sensor, light sensor, gas concentration sensor, acoustic sensor, magnetic field sensor, dust sensor and vibration sensor or other suitable micro-electromechanical (MEMS) sensors.
12. Sensor apparatus (100) according to one of Claims 1 to 11, wherein the housing (120) has a light-transmissive portion (122), in particular an opening.
13. Sensor apparatus (100) according to one of Claims 1 to 12, wherein the sensor apparatus is a house automation sensor apparatus, in particular for internal spaces.
14. Method (200) for producing a sensor apparatus, comprising:

    - producing (210) a housing (120) for at least one sensor (110), wherein the housing has a holder (125) for at least one solar cell (130);

    - producing (220) a cover (140) made of translucent material comprising a fluorescent material through which incident photons of the incoming light are converted into wavelengths in which the quantum efficiency of the solar cell is greater than in the case of the wavelengths of the original incoming light, wherein the cover (140) is adapted to the housing (120), and wherein the production (220) of the cover (140) comprises embedding particles (145) having light-scattering properties;

    - providing (230) at least one sensor (110) in the housing;

    - placing (240) at least one solar cell (130) in the holder (125);

    - establishing (250) an electrical connection between the at least one solar cell (130) and the at least one sensor (110); and

    - mounting (260) the cover (140) on the housing such that the cover (140) covers a photovoltaically active side (131) of the at least one solar cell (130), in particular such that the cover (140) is in direct contact with the photovoltaically active side of the at least one solar cell.
15. Method (200) according to Claim 14, wherein a defined distance is provided between the cover (140) and the photovoltaically active side (131) of the at least one solar cell (130).
16. Method (200) according to Claim 14 or 15, wherein the production (210) of the housing (120) and/or the production (220) of the cover (140) comprises an injection-moulding method and/or an extrusion method.

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